Treatment using 448 kHz capacitive resistive monopolar radiofrequency improves pain and function in patients with osteoarthritis of the knee joint: a randomised controlled trial

Background / Purpose

Knee osteoarthritis (OA) is a leading cause of pain and disability in older adults. While exercise therapy is standard care, its long-term effect size is modest. Capacitive Resistive Monopolar Radiofrequency (CRMRF), also known as Tecar therapy, delivers 448 kHz energy to increase tissue perfusion and metabolism. This randomized controlled trial aimed to determine whether CRMRF could improve pain and function in individuals with symptomatic knee OA beyond standard physiotherapy treatment.

Methods

Forty-five patients (mean age ≈ 62 years) with clinically diagnosed knee OA were randomized into three groups:

• Active group (n = 15): Received 8 sessions of 448 kHz CRMRF (5 min capacitive + 10 min resistive) over 4 weeks, plus standard physiotherapy.
• Sham group (n = 15): Received identical setup but no active energy.
• Control group (n = 15): Received standard physiotherapy only.

Pain and function were assessed using Visual Analogue Scale (VAS), WOMAC Index, Timed Up and Go (TUG), and knee Range of Motion (ROM) at baseline, post-intervention (week 4), and follow-ups (weeks 8 and 16).

Results

Pain (VAS):

• Active group showed a 66% reduction in pain from baseline to post-treatment (mean difference = 1.2 ± 0.3; effect size = 2.5).
• Compared with control and sham, the active group achieved significantly greater reductions at post-treatment (p < 0.01) and 1-month follow-up (p < 0.05).
• Pain relief declined slightly by 3 months but remained 45% below baseline.

Function (WOMAC):

• Active group demonstrated 45% improvement post-treatment (mean difference = 1.9; effect size = 1.5) and 38% at 3-month follow-up.
• Improvement exceeded the minimum clinically important difference and was significantly greater than control (p < 0.05).

Mobility & ROM:

• Timed Up and Go test showed modest, non-significant improvement across all groups.
• Knee range of motion improved only in the CRMRF group (+0.5 radians ≈ +29° flexion).

Overall, no adverse effects were reported, and all participants tolerated therapy well.

Conclusion

Tecar therapy at 448 kHz produced clinically and statistically significant short-term improvements in pain and functional quality of life in patients with knee osteoarthritis. Compared to standard exercise or sham, CRMRF resulted in greater pain reduction (up to 66%) and enhanced mobility over the 4-week treatment period. These findings support Tecar therapy as an effective adjunct to physiotherapy for managing chronic degenerative joint disease, with potential to delay surgical intervention.